Even though our appreciation of the importance and ubiquity of wall slip has grown substantially over the last decade or two, it is still common to find papers on disperse systems wherein scant details of the measurement methods are given and where no mention of the possibility of slip is made. It seems then that there is a need still to raise awareness and to promote the idea that the rheometry of disperse systems is not so straightfoward as it might seem. It takes experience, judgment, and skill to make meaningful measurements on disperse systems and it is suspected that the nature of the experimental challenge is under-estimated grossly by too many workers even now. Slip is not merely a rheometric complication; of course, it an intrinsic feature of the response of disperse systems and one deserving of more attention in its own right. c 2010 The Society of Rheology. [DOI:10.1122/ 1.3495981]